In this specification, both with respect to the prior art and the present invention, reference will be made to grain elevators. However, it will be understood that such references will include other equivalent structures as may be employed for storage of other granular materials apart from grain, such as sand, concrete, gravel and the like.
At the present time, grain elevators assume two principal configurations; either a group of silos with a workhouse at one end, or two groups of silos in line with a workhouse in between. Both forms are provided with auxiliary buildings such as track sheds and shipping galleries.
These elevators, as has been mentioned in my copending application, are limited in height due to the structural design structure of the hoppers, and such hoppers as have been described in that copending application will be employed in the structures of this present application.
The usual method of constructing grain elevator silos is by slip-forming. The workhouse is either constructed by fixed forms or by slip-forms, but because of its shape and structural requirements, it needs more costly form work. The total cost of a workhouse is approximately 50% of the total grain elevator or storage structure. If the slip-form method is used, slabs must be formed and supported for pouring. The resultant structure has limited flexibility, particularly since the columnar arrangement required to provide the requisite strength limits the disposition of equipment and makes maintenance difficult.
Another short-coming which arises from the provision of conventional workhouses is the high possibility of explosion damage due to the generation of dust in the building.
A further difficulty with present structures is the awkward, multiple handling which is required to move the grain through the storage facility and accomplish the various cleaning and storage tasks upon the product. Every movement in present structures must be through the workhouse. At the present time, grain moving through a grain elevator requires at least four upward vertical movements by means of bucket elevators or jack legs. Each such movement causes an estimated 1/2% damage and a total of 2% damage by volume.
Thus, in the prior art, the workhouse is restrictive and inefficient, and grain cannot be received and cleaned in a continuous operation. Also, the standard design of hopper location at the bottom of the silos eliminates any possibility of dividing a silo into stacked bins easily, and the height of bins is restricted because, if bins were higher, the workhouse would be too high.